Poly[9,9-bis(4'-n-octyloxyphenyl)fluorene-2,7-diyl] (PBOPF), and their random copolymers with alkylphenothiazine [poly(BOPF-co-PTZ)], were synthesized through Ni(0) mediated polymerization. Light-emitting devices were fabricated using these polymers in an ITO (indium tin oxide)/PEDOT: PSS/polymer/Ca/Al configuration. Each EL device constructed with a poly(BOPF-co-PTZ) copolymer exhibited significantly enhanced efficiency and brightness compared to devices constructed from the PBOPF homopolymer. The EL device constructed with poly(84BOPF-co-16PTZ) exhibited the highest luminous efficiency and brightness (8,600 cd/m(2) and 2.83 cd/A respectively).